INVESTMENTS - Pretax Other-Than-Temporary Impairment Losses by Investment Category (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Gain (Loss) on Investments [Line Items]
Other-than-temporary impairment losses	$ 977	[1]	$ 1,901	[1]	$ 459	[2]
Credit-related impairment
Gain (Loss) on Investments [Line Items]
Other-than-temporary impairment losses	597		1,286
Change in intent impairment
Gain (Loss) on Investments [Line Items]
Other-than-temporary impairment losses	353		615
Severity and duration of decline in fair value impairment
Gain (Loss) on Investments [Line Items]
Other-than-temporary impairment losses	27
Perpetual securities
Gain (Loss) on Investments [Line Items]
Other-than-temporary impairment losses	243		565		160
Corporate Bonds
Gain (Loss) on Investments [Line Items]
Other-than-temporary impairment losses	345		1,316		285
Mortgage- and asset-backed Securities
Gain (Loss) on Investments [Line Items]
Other-than-temporary impairment losses	3		17		12
Municipalities
Gain (Loss) on Investments [Line Items]
Other-than-temporary impairment losses	0		2		0
Sovereign and Supranational
Gain (Loss) on Investments [Line Items]
Other-than-temporary impairment losses	386		0		0
Equity securities
Gain (Loss) on Investments [Line Items]
Other-than-temporary impairment losses	$ 0		$ 1		$ 2

[1] Includes $597 and $1,286 for the years ended December 31, 2012 and 2011, respectively, for credit-related impairments; $353 and $615 for the years ended December 31, 2012 and 2011, respectively, from change in intent to sell securities; and $27 for the year ended December 31, 2012 for impairments due to severity and duration of decline in fair value

[2] Consisted completely of credit-related impairments